Hi!
 
I am using a Tascam US 122 and Korg NanoKey controller. Up to now i have been able to access my VSti instrument plugins, but now when I want to add one they appear grey on the dropdown list and I can't select any. I can still monitor/record through the US122, and the NanoKey will still play the existing VSTi's that have already been selected. Just can't select new ones. Where did i go worng? Oh, I forgot to mention--in other project files I can still access the VSTi's; I am only experiencing this problem with the current one.
 
Thanks,
Richard

In case anyone sees this and has the same problem---SOLVED!!! It's because too many VSTi's were running. GTP4 has a limit of 8. Even though this project only had 3 actively running, I must have auditioned several which were running in the background even though they didn't show as separate tracks. View>Synth Rack revealed the culprits; I nixed them and we're back on track(ing).

Thanks to the Cakewalk Gurus at Phone Support for bailing me out.